单词O grade
n.: 普通等级考试（苏格兰旧时的单科考试，低于高级考试，通常在 16 岁时参加。1988 年由标准等级考试取代）
普通等级考试（苏格兰旧时的单科考试，低于高级考试，通常在 16 岁时参加。1988 年由标准等级考试取代）:
(in Scotland in the past) an exam in a particular subject, at a lower level than Highers , usually taken at the age of 16. In 1988 it was replaced by the Standard Grade .
o Grade separation, using bridges (or, less often, tunnels) freeing movements from having to stop for other crossing movements
立交，桥梁使用（或很少，隧道）解放运动无法阻止其他过境转移